Effect of anemia on the fasciocutaneous flap survival in a rat model

Objective/Hypothesis: Ablative surgery for head and neck, cancer that creat es large composite defects often results in a significant decrease in the h ematocrit level These defects are best reconstructed with a microvascular f ree tissue transfer, Effect of the decreased hematocrit on microvascular na p survival is controversial. The purpose of this study was to assess the ef fect of isovolemic anemia on nap survival in a rat model, Study Design: Pro spective analysis. Methods: Ninety rats were used (30 control and 60 experi mental animals). Experimental animals were rendered anemic by blood draw an d volume resuscitated with either a colloid (30 animals) or crystalloid (30 animals) solution. In all animals a ventral fasciocutaneous nap was raised . A vascular clamp was applied to the arteriovenous pedicle, and different ischemic times were allowed to elapse before clamp removal. Flap survival w as assessed at 5 days. Probit analysis was performed for the three animal g roups. Results: A significantly increased probability of the nap survival w as found in the anemic animals compared with the control group (P less than or equal to .05). No difference was found between the colloid and crystall oid resuscitation groups. Conclusions: A decreased hematocrit level increas es fasciocutaneous flap tolerance to ischemia and significantly increases t he primary ischemic time in the ventral nap clamp model in rats. Fluid repl acement with either crystalloid or colloid produces identical results.